1. Field of the Invention
The present invention relates to positioning apparatus, and more specifically apparatus wherein a rotating force is transmitted from a driving side clutch shaft to a driven side clutch shaft via a coil spring wrapped around the both clutch shafts, and a cam member fitted around the driven side clutch shaft puts a movable member leaning against the cam member in a specified position.
2. Description of Related Art
In a conventional spring clutch, a coil spring is wrapped around a driving side clutch shaft connected to a drive source and a driven side clutch shaft, and a rotating force is transmitted from the driving side clutch shaft to the driven side clutch shaft by tightening the coil spring. Also, the spring loosens when the rotation of the spring is inhibited, whereby the transmission of the rotating force to the driven side clutch shaft is discontinued.
In this type of spring clutch, however, when the transmission of the rotating force is discontinued by inhibiting the rotation of the coil spring, the driven side clutch shaft does not stop rotating immediately and continues rotating by a slight angle because of inertia, that is, overruns. Then, a cam member fitted around the driven side clutch shaft overruns, and a movable member to be positioned by the cam member is not put in place accurately.